Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 108 ppsx

Cervical closing wedge osteotomy corrects severe cervicothoracic kyphosis A fixed cervicothoracic kyphotic deformity is rare Case Study 1.. Treatment for Fracture and Spondylodiscitis F

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a b

Figure 5 Multisegmental posterior wedge osteotomy

This technique creates lordosis and is usually applied to one or multiple levels.aThe spine is instrumented with pedicle screws two levels above and below the planned osteotomies.bThe interspinous ligament and the adjoining spinous process are resected with a rongeur The yellow ligament is removed and v-shaped bilateral osteotomies are carried out through the isthmus.cThese osteotomies are directed laterocranially at an angle of 30 – 40 degrees The desired slot width of 5 – 7 mm is obtained by using appropriate rongeurs If there is a scoliotic deformity, the osteotomies are made slightly larger on the convex side.dThe rods are applied first cranially The osteotomy gaps are closed by stepwise seg-mental compression and connection to the rods A posterior spinal fusion is added With one single osteotomy approxi-mately 10 degrees of correction can be achieved

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Cervical closing wedge osteotomy corrects severe cervicothoracic kyphosis

A fixed cervicothoracic kyphotic deformity is rare ( Case Study 1 ) However, this

deformity can cause a significant morbidity because of an impingement of the

chin with the chest, making eating and drinking difficult Furthermore, patients

lose their horizontal gaze A cervical corrective osteotomy was first described by

Urist in 1958 [95] The opening wedge osteotomy was originally carried out at the

level of C7/T1 during local anesthesia The osteotomy level is chosen at the

cervi-cothoracic junction because the vertebral artery only enters the spine at the level

of C6 With the advent of neuromonitoring, these interventions can today be

per-formed with the patient under general anesthesia and with less stress for the

patient The disadvantage of the opening wedge osteotomy is the resulting

ante-rior gap with potential instability and need for an additional anteante-rior fusion

( Case Study 1 ) The correction of kyphosis can be balanced up to the level of

lor-dosis and corrections have been reported up to 54° [70] Webb advocates a

clos-ing wedge osteotomy because of a better stability without the need for an

uncon-trolled cracking of the spine to achieve the correction [104] ( Fig 6 ) Method of

choice is a closing wedge osteotomy with or without an anterior interbody fusion

depending on the fusion status of the anterior column Case reports of chin on

chest deformities so far show excellent resolution of the deformity and solid

fusion [73] Retrospective studies show that cervical spine surgery in AS appears

to have a fairly good clinical outcome [56] (Table 7) However, this osteotomy is

very demanding and carries a high risk of neurological injuries [60, 70].

Treatment for Fracture and Spondylodiscitis

Fractures are most common

at thoracic level and unstable

Fractures in AS patients are most commonly localized at the thoracic spine and

are very often unstable because they involve the anterior and posterior column

[10, 34, 77, 84, 109] In contrast to a healthy individual, AS patients sustain

frac-tures more easily from minor trauma and experience fatigue fracfrac-tures These

fractures often remain occult (see above) as clinical symptoms are masked by

chronic pain Not infrequently, the spine spontaneously corrects its kyphotic

deformity within the fracture ( Case Study 2 ) Thirty to 75 % of cases are

associ-ated with severe neurological deficits [10, 34, 42, 77].

Instrumentation should be long rather than short in AS

The general concepts of treatment also apply (see Chapters 30 , 31 , 36 ) for

spinal injuries in AS and aseptic spondylodiscitis (Andersson lesions) In

con-trast to common fractures and spondylodiscitis, however, the stabilization

should be long rather than short because of the risk of a secondary kyphotic

deformity, implant failure and non-union The degree of instability in AS

deter-mines the use of long instrumentation over a minimum of two vertebral bodies

above and below the lesion [59] Laminectomy is indicated when defective

posi-tions or bony hypertrophy leads to constriction or stenosis of the spinal canal or

in the presence of epidural hematoma Operative fracture stabilization is

pre-ferred to allow for early mobilization of the patient However, treatment of spinal

fracture causing paralysis is difficult and controversial and is associated with

a high risk of complications [4, 10, 34, 42, 77, 78, 109] Surgical management

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a b

c

d

Case Study 1

A 58-year-old male was diagnosed with ankylosing spondylitis, which had been present for over 20 years The patient was severely handi-capped by his inability to look straight ahead (a) The standing lat-eral radiograph demonstrated a sag-ittal well balanced spine with the deformity located at the cervicotho-racic junction (b,c) A cervical open-ing wedge osteotomy at C7 was done (d) The spine was stabilized with facet joint screws at C4 and C5 and pedicle screw fixation at T1 (e)

In a second stage, an anterior inter-corporal fusion and plate/screw fixa-tion was added to close the gap and additionally stabilize the spine (f) Postoperative photograph (g) shows

an excellent correction of the posi-tion of the head

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a b

Figure 6 Cervical closing wedge osteotomy

For this osteotomy the patient is positioned prone within a Mayfield headrest Sensorimotor potentials should be

obtained prior to surgery as a baseline measurement.aThe spine is exposed from C4 to T3 Pedicle screws are inserted

three levels above and below the osteotomy In the cervical spine, facet joint screws can be used as an alternative to

pedi-cle screws because of a lower risk of neurovascular injuries The lamina of C7 and the hemilaminae of C6 and T1 are

resected Care has to be taken to completely liberate the nerve roots C6 – 8.b The articular processes of C7 are

completely removed including the C7 pedicles The vertebral body of C7 is decancellated with curettes and the posterior

wall osteomized with a Kerrison rongeur.cBoth rods are inserted and locked in the cervical screws.dThe Mayfield

head-rest is loosened by an assistant who continues to manually hold the head during the correction The rods are slowly

levered to the thoracic screws and locked Great care has to be taken that the head extension does not result in a

com-promise of the nerve roots A posterior spinal fusion completes the operation

Treatment of fracture causing paralysis is associated with a high risk

of complications

of fractures or lesions in AS should be done in specialized interdisciplinary

clinics The reasons are the high rate of complications (e.g., neurological

fail-ure, loss of fixation, wound infections, respiratory failure) and mortality

post-operatively.

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a b

e

f

Case Study 2

aA 59-year-old male who had suffered from ankylosing spondylitis for three decades was well adapted to his disease He sustained a fall on the stairs and complained of weakness in his legs At hospital admission the patient had a mild paraparesis sub-L1 with decreased sensation and mild weakness in both legs (MRC Grade 4) CT reformatted image (b) shows a luxation fracture at L1 with significant posterior angulation of the spine T1 and T2W MRI scans (c,d) demonstrate the luxation fracture and significant canal enchroachment The previously ankylosed kyphotic spine corrected at the level of the fracture After decompression of the spinal canal, the patient was instrumented with a pedicle screw system in the corrected position Fusion was added at the site of the frac-ture (e) At one year follow-up visit, the patient had completely recovered and was very satisfied with the correction of the trunk position, which had bothered him for many years prior to his fracture (f)

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et al.

(1997) [70]

spective OT with (n = 3)

and without

(n = 12) internal

fixation

2 irreversible neurological complication

1 deep wound infection

4 subluxation

1 major general complica-tion

ficult techniques Subluxa-tion at the osteotomy site is associated with non-union

Willems et

al (2005)

[108]

105

cervical-thoracic and lumbar

retro-spective

cervical-thoracic

OT (n = 22),

lumbar

closing-wedge OT (n = 62),

polysegmental lumbar OT

(n = 20),

anterior-posterior

lumbar OT (n = 11)

8 transient paresthesia

correction osteotomies in

AS show high complication rates Reasons are a difficult surgery and a complex dis-ease AS surgery should be carried out in specialized interdisciplinary centers

Danisa

et al

(2000) [33]

11 thoracic

and thora-columbar

retro-spective

“eggshell” osteo-tomy

an “eggshell” osteotomy shows lower complication rates than with open wedge osteotomies Main goal of this procedure is to restore sagittal balance

Van Royen

et al

(1998) [98]

21 thoracic

and thora-columbar

retro-spective

polysegmental lumbar oste-otomies are associated with high complication rates

Only in the mild phase of

AS should a polysegmental lumbar osteotomy be used

Hehne et

al (1990)

[47]

177 thoracic

and thora-columbar

retro-spective

the technique results in a harmonious spinal correc-tion And reduces the potential of severe compli-cations Most patients are pain free after polysegmen-tal lumbar OT

Bradford

et al

(1987) [14]

21 thoracic

and thora-columbar

retro-spective

open wedge OT

(n = 8), two stage

osteotomy (ante-rior and poste(ante-rior)

(n = 8)

a neurological monitoring with a wake-up test is nec-essary A correction of sagit-tal balance seems to be associated with decreased risk of loss of correction

Lazennec

et al

(1997) [63]

31 lumbar

retro-spective

open wedge OT

(n = 19) vs close wedge OT (n = 12)

3 reoperations (non-union)

vs

1 reoperation (non-union)

the level of lumbar osteo-tomy is very important, because sagittal translation

is a basic mechanism for correcting sagittal imbal-ance

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Surgical interventions for AS most often represent major surgery and are techni-cally demanding Not infrequently patients exhibit malnutrition and are prone to infections The morbidity and mortality rate can be decreased by careful surgical planning, new operating techniques, new implants and improved intensive care

[26, 28, 29, 47, 60, 63, 72, 82, 86, 92, 100] Complications after ankylosing surgery include [28, 60, 98, 100, 108]:

) transient paresthesia (0 – 45 %) ) postoperative infections (0 – 33 %) ) implant failure (2 – 33 %)

) loss of correction (5 – 40°) ) irreversible neurological deterioration (0 – 10 %) ) major general complications (0 – 10 %)

) non-unions (< 5 %) Surgery for AS is prone

to complications

These interventions are related to a long operative time, high loss of blood and a high rate of peri- and postoperative complications Therefore, indications need

to be discussed on an individual basis and patients have to be consulted exten-sively.

Recapitulation

Epidemiology. Ankylosing spondylitis (AS) is a

sys-temic seronegative inflammatory rheumatic

disor-der belonging to the group of spondyloarthritis.

AS is associated with sacroiliitis and inflammatory

alteration at the axial skeleton The male:female

ra-tio is about 2 – 7:1 Prevalence estimates vary

be-tween 0.2 and 1.2/100 000 The peak age of onset is

15 – 35 years The diagnosis is delayed by up to

10 years, because of its insidious nature.

Pathogenesis. The pathogenesis is still unclear.

There is increasing evidence that AS is genetically

determined AS has a strong association with

HLA-B27 and 90 % of all patients are HLA-HLA-B27 positive.

However, 80 – 90 % of all HLA-B27 carriers do not

de-velop AS It is therefore widely assumed that

addi-tional genetic factors are involved An

infection-triggered onset has recently been added to the

ex-isting hypothesis This concept involves a

preced-ing bacterial infection with subsequent

autoim-mune responses The pathological changes of the

vertebral column due to AS occur in three

consecu-tive stages: inflammation, proliferation and

anky-losis.

Clinical presentation. Patient complaints are

non-specific and difficult to distinguish from general

chronic back pain Cardinal symptoms are

inflam-matory back pain, typical arthritis pain (pain at

night and stiffness in the morning), progressive

spinal stiffness and the inability to look straight

ahead Additional symptoms are enthesis, uveitis, pulmonary, cardial and bowel inflammation as well

as reduced chest expansion.

Diagnostic work-up. Early diagnosis of AS can be difficult due to unspecific symptoms and diagnos-tic findings of the spinal column In the case of sus-picion of AS, the diagnosis should be enforced The diagnostic work-up includes a thorough clinical

ex-amination, laboratory investigations (infection

pa-rameter, HLA-B27) and imaging studies The goal is

to detect AS in the early disease so as to commence therapy in good time In the early disease stage,

MRI is the state-of-the-art diagnostic tool

Charac-teristic findings on MRI suggestive of AS are discitis, erosions with zones of subchondral sclerosis with-out increased signal after use of a contrast agent,

periarticular fat accumulation and

syndesmophy-tes Alternatively, a bone scan can be of further

di-agnostic use Radiographs and computed

tomog-raphy are suitable tools for monitoring chronic

in-flammatory progression Furthermore the CT can

be utilized for preoperative planning Following a trauma and suspicion of lesion or fracture radio-graphs, CT and MRI of the whole spine should be performed.

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[ inhibitors Physiotherapy and patient education are in parallel to medical

treat-ment cornerstones of AS therapy.

Operative treatment. Surgery is of value when

con-servative therapy fails, i.e., in the case of massive

kyphotic deformity or severe pain Absolute

indica-tions for surgery are unstable spinal fractures,

kypho-sis-related progressive myelopathy and progressive

spondylodiscitis Surgical correction in AS patients is

prone to a high peri- and postoperative complication

rate (such as neurological deficits, deep wound

infec-tions, failure of implants) However, the morbidity

and mortality rate can be decreased by careful

surgi-cal planning, new operating techniques, new

im-plants and improved intensive care An important

aspect is the perioperative anesthesia Patient

posi-tioning and intubation are often very difficult due to

kyphotic deformation Intraoperative

neuromonito-ring is nowadays regarded as indispensable for a safe

deformity correction.

The ultimate goal of surgical techniques of

osteo-the thoracic spine and to allow for a harmonic bending of the spine Four to six thoracic or lumbar levels can osteotomized depending on the extent and location of the spinal deformity.

Corrections at the level of the cervical spine are

performed at the C7/T1 level The procedure of choice is a closing or opening wedge osteotomy in combination with an instrumented fusion Cervical spine surgery in AS appears to have a fairly good clinical outcome, although it is a very demanding operational procedure with a potentially high risk

of neurological injuries.

Fractures in AS patients can already appear after

minimal trauma and are often overlooked Most often, fractures appear in the thoracic spine and are frequently unstable because they involve the ante-rior and posteante-rior spinal column In 30 – 75 % of cases there is an association of severe neurological deficits.

In contrast to common fractures, however, the stabili-zation should be long rather than short because of the risk of a secondary kyphotic deformity.

Key Articles

van Royen BJ ( 1995) Closing-wedge posterior osteotomy for ankylosing spondylitis.

Partial corpectomy and transpedicular fixation in 22 cases J Bone Joint Surg Br 77:

117–121

This retrospective study with closing wedge osteotomy at lumbar level L4 shows that this

surgical procedure is effective in addressing the kyphotic deformity

Murrey DB ( 2002) Transpedicular decompression and pedicle subtraction osteotomy

(eggshell procedure): a retrospective review of 59 patients Spine 27(21):2338–45

The eggshell procedure was described and analyzed retrospectively in 59 patients with

deformity (n = 37) and tumor or infection (n = 22) This surgical procedure is safe and

predictable for complex spine deformities

Hehne HJ ( 1990) Polysegmental lumbar osteotomies and transpedicled fixation for

cor-rection of long-curved kyphotic deformities in ankylosing spondylitis Report on 177

cases Clin Orthop Relat Res 258:49–55

This is a retrospective study with a high number of polysegmental lumbar osteotomies in

patients with AS The authors describe surgery procedure, correction of spine

postopera-tively up to 18 months follow-up and associated complications

Urist MR ( 1958) Osteotomy of the cervical spine; report of a case of ankylosing

rheuma-toid spondylitis J Bone Joint Surg Am 40A:833–43

Classic article on the cervical opening wedge osteotomy for AS

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Smith-Petersen M, Larson C, Aufranc O ( 1945) Osteotomy of the spine for correction of flexion deformity in rheumatoid arthritis J Bone Joint Surg Br 27:1–11

Classic article on an opening wedge osteotomy in the thoracolumbar spine and V-shaped thoracic osteotomies for AS

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